Design of conformal, substrate-independent surface modification for controlled proteinadsorption by chemical vapor deposition (CVD)

Abstract

Biofouling is a crucial consideration in a variety of applications including biosensors, biomedical implants and devices, food packaging, and industrial and marine equipment. On the other hand, the controlled adsorption of proteins is desired in certain fields such as bioassays and tissue engineering. As such, significant progress has been made in fabricating surface chemistries that are able to resist or regulate protein adsorption through the manipulation of the protein-water-surface interactions. However, a conformal, substrate-independent surface modification method is required in order to extend such chemistries to a wider range of applications including delicate substrates, nanostructured surfaces, and polymer nanotubes. Here, we review the chemical vapor deposition (CVD) of coatings to control protein adsorption. These CVD coatings can be classified into four categories: hydrophilic coatings or hydrogels, which resist protein adsorption through surface hydration; fluorinated coatings, which have especially been studied in the context of fouling release in marine environments; amphiphilic coatings involving a unique antifouling mechanism; and switchable or stimuli-responsive coatings. Many of the techniques in each group are compatible with the synthesis of surface or freestanding nanostructures, and can be easily integrated into the existing fabrication infrastructure.

Modification of membrane surfaces via microswelling for fouling control in drinking water treatment

“…However, currently available methods have found limited use due to their drawbacks. To increase the surface hydrophilicity of a membrane, hydrophilic moieties may be coated [23][24][25] or grafted [26][27][28] to the membrane surface. In either case, additional mass transfer resistance is introduced to the membrane surface [14].…”

Molecular fouling resistance of zwitterionic and amphiphilic initiated chemically vapor-deposited (iCVD) thin films

“…[4] These hydrophilic surface chemistries all demonstrated fouling resistance close to polyethylene glycol, an FDA-approved biopolymer that is often considered as the gold standard in protein resistance. [5] Amphiphilic surfaces represent another interesting category of antifouling chemistry that does not rely on the film's hydrophilicity.…”

“…The amphiphilic and zwitterionic surfaces were synthesized with the same polymerization technique, namely initiated chemical vapor deposition (iCVD, Figure 1). [4,15] iCVD is a facile method to carry out free radical polymerization in the vapor phase, enabling the synthesis of insoluble and infusible polymers in a single step. For instance, amphiphilic polymers, which are challenging to synthesize using solution phase methods due to the lack of a common solvent for two comonomers with contrasting solubility, are easily obtained via iCVD with flexible compositional tenability.…”

Surface modification of reverse osmosis membranes with zwitterionic coating for improved resistance to fouling

“…Zwitterionic materials have been extensively explored for their ultra-low protein adsorption [14] and as hydrophilic or foulingresistant modifiers [15][16][17][18]. Bãrboiu et al have prepared macromolecular carboxybetaines by reacting vinyl pyridine polymers with α,β-unsaturated carboxylic acids.…”